1. Field of the Invention
The present invention generally relates to plumbing devices and more particularly to an improved device for temporarily plugging drain pipes in order to test the same.
2. Prior Art
When a new home, condominium or apartment house or the like is constructed, the drains must be tested for leaks before they can be approved by an inspector. This is usually accomplished by first inserting a temporary plug device through the clean-out pipe located outside the structure to a point where it intersects a sewer line running from the structure drain to the main sewer line.
Such plug device usually is a long hollow expandable sausage-like unit which has a nipple at one end through which air or another gas is introduced into the unit until the unit expands sufficiently in diameter so that one end thereof blocks the clean-out pipe and the other end thereof seals off the sewer line. Water can then be introduced into the house drain and sewer system to check for leaks.
Such a conventional plug device has several drawbacks. Thus, such device is usually difficult to slide into place and to retrieve, due to its shape. Moreover, when the device is deflated, the fluid from the house drains not only flows into the sewer line but also backs up through the clean-out pipe, especially in multi-storied structures, creating a sanitation hazard. In addition, if the device is subjected to excessive pressure during use, it will rupture, with possible serious injury to workmen and the plumbing and sewage system.
Improved gas-expandable drain pipe plug devices have been devised by the present Applicant and are set forth in U.S. Pat. Nos. 4,660,603 and 4,790,356. Those devices overcome many of the drawbacks described above for conventional drain plugs.
However, there remains a need for a further improved drain pipe plug device which does not depend on introduction of gas therein to expand the device, since in some instances the use of gas is inconvenient. Such device should not be subject to rupture and possible injury to workmen and the structure drain pipe and sewage system. Preferably, it should provide means for bleeding off the head of test water in the drain pipe after the test thereof is completed, so that the test water does not gush out the drain pipe access hole or clean-out pipe through which the device has been introduced, when the device is removed therefrom.
Moreover, the improved device should be simple, durable, inexpensive, capable of being operated by a single workman and have a positive locking means indicating it is in the full operative position so that the test can begin.